Mill



Nov. l2, 1940.

E. A. BUTLER 2,221,342

MILL

Filed March 30, 1938 `75 Sheets-Sheet 2 FiQAm i117 Mi ATTORNEYS NOV. l2, 1940..` E A, BUTLER 2,221,342

MILL

Filed March .'50, 1958 3 Sheets-Sheet 5 INVENTOR N I Eawgmmmer,

ATTORNEYS Patented Nov. 12, 1940 PATENT OFFICE MILL Edward A. ButlenBuifalc, N. Y., assignor to The Turbuletics Corporation, Buffalo, N. Y.

Application March 30,

4 Claims.

This invention relates to improvements in` colloid mills or machines for the minute disintegration and/oncomminution of otherwise immiscible substances.

It is generally well known and understood that mills for the minute disintegration of substances such as are used in connection with the preparation of emulsions, colloidal suspensions and dispersoids, may employ the principle of particle collision or impingement, Vand shearing action which may beset up in a thin layer of liquid carrying solid particles, as a result of rapid movement of the opposing sides of the layer in opposite directions. This action may be induced through adherence of` the mill feed material to relatively moving mill surfaces. The moving members of mills of this type travel at high rates of speed and are usually provided with cylindrical, conical, or disc-like surfaces, the rapid rotation of which set up centrifugal forces tending to segregate the component elements oi the mill feed materials according to different viscosity, speciiic gravity, or other physical characteristics. This centrifugalization tends to result` in accumulation and packing ofsolid particles from the feed material against the walls ofthe mill and particularlyin the regionrcomprising the pre-milling chamber between the feed inlet and the zone in which the milling processactually takes place. Thus solid material tends to accumulate'in the mill to a point where it contacts the moving member of themill', and the friction resulting from this contact generates heat as a `result of which the material may burn or melt, thus spoiling the product and/orgclogging the mill.

Variations of temperature in mills of this'type invariably cause alterationsin the physical proportions ofthe various members of the mill, thus effecting the spacing between the relatively movable members and causing frictional ,heat and/or alteration of product sizes. `Alsoin this type of machine the rapid rotation allyshaped mill member in connection with the milling process has heretofore imposed centrifugal `forces upon the material' passing `through the mill tending to increase the speed of the higher specific gravity particles through the mill, thus destroying the homogeneity of the yield and cutting short the milling action. It has therefore been diiiicult to provide a niilltthat would operate on manyV kinds of substances required for industrial purposes that is capable oflyielding the desiredpro'duct and performing with uniform results over extended periodsof time.` Oneobject of the invention is to provide a of the disc or conic- 1938, Serial No. 198,945

mill construction in which reduction of particle size and/or dispersion of particles in emulsion products is effected in accordance with commonly accepted principles, but with increased efficiency of operation. t e Another object of the invention is to provide in a colloid mill construction utilizing closely arranged relatively movable film carrying surfaces of the conical type yan improved arrangement and disposition of parts whereby undesirable centrifugal action is obviated which would otherwise tend to speed the passage of material through the mill before completion of the dsintegrating process. Another object of the invention is to provide in a mill of this type means for preventing segregation of component elements of the mill feed material as a result of centrifugal action set up by the rotating members, and accumulation of solid particles upon the relatively movable members of `the mill, thus obviating the possibility of frictional` burning of the mill feed substances and/or clogging of the mill.

Another object of the invention is to provide in a ne grinding mill an improved construction embodying means for convenient .adjustment of the relatively `movable members to yield different sized products and to compensate for variations of the relative positions of `the stationary and movable members thereof such as may result from temperature changes therein.

Another object of the invention is to provide an improved mill construction for treating fluids containing solids wherein concentration of the mill feed 4material in the milling zone may be controlled ,by an improved pressure regulating means convenientlypositioned externally of the mill, whereby the rate of impingement action between the solids in the feed material may be regulated at will to control the degree of solid particle disintegration. e

VAnother object of the invention is to provide an improved mill construction for treating normally immiscible liquid mixtures wherein the rate of impingement actionbetween droplets of the liquids may be regulated to control the degree of droplet disintegration and comminution.

Another object of the invention is to provide in an improved mill construction' of the type employing members movable relatively one to another at high rates of speed, means for preventing segregation of solids and/or liquid portions of the mill feed material as a resultof centrifugal action, whereby the mill feed materials pass through the mill in a homogeneous state.

The invention is exemplified in a construction employing a generally funnel shaped shell or stator and a conically shaped rotor mounted concentrically therein for rotation relatively to the stator. A feed inlet is provided at the apex of the stator for introduction of the mill feed material between the opposed surfaces of the rotor and stator members. The apex portion of the rotor is provided with a plurality of mill feed diverting conduits Vwhich are in open communication w'ith an axially disposed mill feed receiving conduit in line with the mill feed inlet to receive a portion of the incoming mill feed. The feed diverting conduits extend radially and latervally through the body of the rotor, and are thus adapted, by reason of centrifugalv action set up by rotation of the rotor, to discharge' streams of feed material laterally against the adjacent lwalls of the stator for disrupting any segregating tenddency in the mill feed material prior to its passage between the milling portions of the rotor and stator, and to breakup any accumulation of solid particles on thewalls of the mill.

By-pass ports extending radially in spaced relation through the adjacent portions of the stator receive a portion of the laterally discharged feed material for conveyance through suitable connecting return conduits to the original source of mill feed supply, thus relieving excessive pressures in the premilling chamber.

The rotor is of the general shape of a cone generated by a line inclined at 15 to the longitudinal axis thereof, as it has been found as a result of exhaustive experiments that centrifugalization forces resulting from the rapid rotation of a cone'of this degree produces no appreciable segregation of the mill feed mixed materials or acceleration of the passage of heavier particles of the mill feed material through the `milling zone.

stator and rotor members for controlling temperature conditions in the mill. An improved automatic, simple and effective lubricating means forthe rotor bearings is provided.

In the drawings:

Fig. 1 is a fragmentary view, partly in elevation and partly in section, of the milling portion of an apparatus incorporating the invention;

Fig. 2 is a diagrammatic view of the complete apparatus;

Fig. 3 is a section, on an `enlarged scale, lthrough the pre-milling chamber and a'portion of the milling zone of the mechanism shown in Fig. 1;

Fig. 4 is a view, partly in elevation and partly in section of another form of milling head and shaft construction;

. Fig. 5 is a section taken substantially along line V-.V of Fig. 1;

. Fig. 6 is a section taken substantially along line vvI--vf of Fig. 1. Y

, Referring to the drawings, a frame member lIll is mounted rupon Va conventional type electric Lmotor I2by means of bolts I4 in such manner that the motor provides vabase for the device.

The motor base I2 is adapted to be arranged upon any suitable supportl such as a stand I6 (as shown in Fig. 2) for support upon a floor, or by suspension from above in any conventional manner. The frame I is in the form of a generally cylindrical upright casting, and rotatably carries therein a r'otor shaft 3|.'I by means of a pair of spaced bearings 32 and 33 respectively. At its lower end, the shaft 30 is connected to the extending end 40 of the armature shaft of the motor I2 by means of a coupling 42 of the conventional exible type.

The upper end of the shaft 3l) is provided with a slightly tapered section 38 adapted to receive in tight-fitted relation thereon a centrally bored rotor head member U. The bore of the head 5U is tapered to correspond to the tapering of the section 38 of the shaft 30 for accurately and firmly positioning the head 50 upon the shaft 3B. An intermediate portion of the head 50 is provided with an enlarged bore as at 54 to allow for the unequal expansion of the material forining the head under varying temperature conditions, which might otherwise impose dangerous stresses in the material forming the head 5U. The head 52, is provided with a smoothly machined outer working surface 56 extending about the majority of the longitudinal extent of the head and tapered uniformly at an angle 0f approximately 15 from the longitudinal axis of the head. As shown clearly in Figs. 3 and 4 immediately adjacent its upper end, the head 5l! is provided with an increased degree of taper, as at 51.

A cap member 65 for the head 5l] is provided in the general form yof a truncated cone and is provided in its lower portion with a central bore to receive the extreme upper end of the shaft 3U and a downwardly extending annular threaded portion B8 adapted for cooperation with a threaded recess in the upper end of the head 50. Thus the cap 65 provides a closure for the upper end of thel head 50. A lock nut 5I engages the. upper threaded end portion 52 of the shaft 30, thus detachably maintaining the head 50 on the shaft 30. The lock nut 5I is formed with a laterally extending flange 53 at its lower end forbearing against a thrust ring 55 positioned in the head 50, thus limiting the upper movement of the lock nut 5I.

To assemble the component parts of the milling head unit, the lock nut 5I is first inserted in the recess in the upper end of the head and the thrust ring is then threaded into its position, thus retaining the lock nut 5I in the head. The upper end of the shaft 30 is then inserted through the bore of the head 50 to a position wherein the threaded end 52 of the shaft engages the threads of the lock nut 5I. The lock nut 5I is then rotated by means of a suitable wrench, thus drawing the threaded end of the shaft 30 into the lock nut and forcing the tapered section 38 of the shaft into the tapered central bore of the head 50 to a firmly seated position. The cap 65Y is then threaded into position upon the upper end of the head 50, thus sealingv the connection between the shaft and the head. y To disassemble the milling head unit, the cap 65 is first removed and the lock nut 5I is then rotated by means of a wrench. The flange 53 of the lock nut bears upwardly against the thrust ring 55, and thus the unthreading movement of the lock nut generates longitudinal thrust forces between the head 50 and the shaft 3U, thus forcing the shaft 30 out of the head.

The bearing members 32 and 33 are'of a conventional kball bearing assembly type, eachi-com'- prising an outer race 34, aninner race,35'and an intermediatelypdisposed series of `steelballs 36. `Portions of the frame member r|0 immediately adjacent the bearings 32 and 33are.pro vided with accurately machined annular surfaces to laterally position the outer bearing races 34. The inner races 35 bear laterally against correspondingly machined surfaces of theshaft 30. Shoulders 72 are provided onthe shaft 30 for cooperation with upper and lower lock nuts 14 and 16 which are threaded upon the shaft 30 to maintain the inner races 35 in proper position longitudinally of the shaft. A pair of locking `rings '|8, threaded intou the frame I0, bear against opposite ends of the `outer races.34 to position the bearings 32 and 33 longitudinally with respect to the frame I0. Thus `the shaft 430 is supported in an upright position in the frame 0 for rotation relative to the frame.

A saddle piece 90 in the general form of a cylindrical casting is mounted upon the upper end of the frame |0 by means of a pairlof spaced annular steps 98 and |02 formed on the frame I0 in such manner as to be concentric with the casing and the milling head and shaft. The saddle 90 is shaped at its lower end as an annular l flange having a lower face 94 and an adjacent inner vertical face 96.` Thus, theannular step 98 on the frame |0 is adapted toreceive the flange of the saddle in close tting relation thereon and to position the saddle 90 upon the frame |0 both laterally and longitudinally. A series of studs |00 arranged in` radial spaced relation about the step 98 are provided to detachablymaintain the saddle 90 in assembled position upon the frame.

The upper end of the frame |0 is formed with an annular flange |02 spaced at a substantial distance fromV the step 98l both longitudinally and laterally of the machine, being of smaller diameter than the step 98 and at an elevated position therefrom. A concentric annular vertical bearing surface |04 is formed on the adjacent portion of the saddle casting 90 for coperation with the flange I 02 to position the saddle 90 laterally with respect to the frame I0. Thus thev saddle casting 90 is firmly supported upon the frame by a pair of supporting surfaces which are spaced one from another both laterally and longitudinally of the machine. Unequal longitudinal movements at opposite sides of the mill between the saddle 90 and thestep 98 will alter the angular relation of the longitudinalaxes of the saddle and the frame, the saddle pivoting upon the contact between the flange |02 and the bearing surface |04. Thus adjustments ofthe angular relation between the saddle 90 and the frame |0 may be accomplished by loosening the studs |00 and inserting suitable shims between the step 98 and the saddle at the proper points. Hence, variations from proper axial alignment of theframe and the saddle member such as may occur asa result of temperature changes or imperfect machining of parts, may be corrected. The upper end of the saddle is internally threaded as at |2 to receive in threaded relation therein a stator milling member |20; ,The stator is `of an outer cylindrical' form, and is provided centrallywith a longitudinal tapered bore. The'jcentral bore is accurately machined to provide a conical milling surface` |22 which conforms to the general shape of the rnillfheadA 50. The stator |20 is adapted,1r by reason of itsthreaded mounting in the saddle 90 for'a'djustment longitudinally of the mill to various spaced positions with respect to the milling head 50. Thus means are provided to varythe width ofthe milling gap between the surfaces |22 of the stator and 56 of the rotor. The threads ||2 are formed in such manner as to be relatively loose fitting and to allow a small amount of lateral relative movement between the stator |20 and the saddle 90. A series of studs |30 arranged at intervals around the saddle 90 are threaded into openings through the saddle and are adapted to bear against the stator 20 to provide means for shifting the stator |20 laterally relative to the saddle.. Lock nuts |3| hold the studs |30 in adjusted positions. Thus minor adjustments of the position of the stator may be made to compensate for improper alignment ofthe parts such as may be due to imperfect machining and/or operating temperature changes.

A locking ring IZB-encircling the upper` end of the stator |20 and in threaded relation therewith, provides means for accurately positioning and maintaining the stator |20 in parallel' axial relation with the saddle 90 in every position of its adjustment. l o

A dome |32 of a generally cylindrical outer form and provided with a conically shaped central bore in the lower end `thereof is mounted upon the` upper end of the stator-member |20 by means of bolts |33. A mill feed inlet port |34 is formed centrally through the upper end of the dome |32 and in open communication with the apex ofthe cavity in the lower `end of the dome. 'I'he bore of the dome conforms to the shape of the tapered cap B5 of the milling head, and provides therebetween an annular premilling chamber for the even distribution of mill feed material from the inlet port |34 about the upper end of the milling gapl between the surfaces |22 and 56 of the stator and the milling head respectively. The tapered portion 51 of the milling .head 50 provides an intermediate step `between the surface of the cap and the surface 56 of the head to automatically provide a pre-milling gap of a `width greater than that of the milling gap in every position of milling head adjustment. l

The milling head cap 65 is provided with an axially disposed vinlet port 60, extending from the upper or apex end thereof downwardly and in line with the mill feed inlet port |34 to an intermediate position in the cap where it joins in open communication with a plurality of radially disposed discharge ports 62 extending laterally tothe outer surface of the cap. The inlet port 60 is of smaller dimension than that ofthe mill feed inlet port |34 of the dome. As shown in Fig. 3 a plurality of radially disposed by-pass channels |36 are formed through the dome |32 commencing from a position intermediate of the p pre-milling chamber and extending to the outside ofthe dome |32 for connection with a manifold collecting conduit |40lwhich in turn communicates with the original mill feed supply tank |45 through means of a conduit |4|. An inlet conduit |41 of conventional type conducts `the liquid mill feed material to the mill in re.-

sponse to pressure generated by a pump |48 in the feed inlet line.V A valve |42 is located in the line of the conduit |4| whereby the operator of the machine may regulate at will the fluid pressure within thelmill. A gauge |43 is provided in the manifold |40 to appriselthe operator of pressure conditions therein.

tated by means .of the "motor '|2, and mill feed 'material is introduced intol'thedome |32A by koperation of theupump |43. A portieri of the mill feedmaterial entering the pre-milling chamber between the conically-shaped` surfaces Aof the cap land 'the dome |32 travels `downwardly toward the vmilling `zone between the head 50 and the stator |20. The rapidly rotating movement of the-milling head tends to impart a circular or spirally descending movement yto this portion of the mill feed material as it passes through the pre-milling zone, and vcentrifugal forces `set up in thefeed material tend to cause `segregation of .the component parts thereof because oftheir different viscosities, specific .gravities Yand/orl other physical characteristics. Another portion of .the incoming mill feed material, however, enters directly the port 60 of the cap '65, andtravelsfdownwardly and thence laterally -into the discharge ports' 62; and due to the centrifugal action. set 11p-by the rapid rotation of the cap;` this portion of -the feed material is impelled outwardly with great force through the ports 62 and is thrown transversely into the adjacent section of the pre-milling gap. Thus therapidly rotating cap member 65 engages a portion of the 'incoming mill feed material, di- Verts its course, and throws it outwardly in a circular path in almanner similar to the action of an impeller of a centrifugal pump.l

As shown in Fig. v,the by-pass ports `|256 are yso disposed in the dome |32 that-they open into the .pre-milling gap' in positions substantially within the section-` of the prevmilling gap into which the ports 62 of the cap 65 discharge their portion of the feed material. The by-pass ports |35 are preferably so arranged, however, that the centersof their openings into the pre-milling gap are at points slightly above the center line of thedischarge ofthe ports 62, so that the discharge from the ports 62 is divided into two courses, one of which enters directly the by-pass ports |36, and the'other of which. strikes the opposing wall of the dome |372. and is then defao flected downwardly and in to themilling vgap of the machine.

.As illustrated in Fig. 3,'there is thus Vprovided means for constantly disrupting any tendency of segregation of the mill feed material in the premilling gap due to centrifugalization or other cause, thus `insuring the delivery vof a homogeneous mixture of mill feed material to the milling gap of the machine. The'rapid Ieruption of mill feedlmaterial fromthe ,dischargeV .ports 02 across `.the pre-milling'gapand ltoward the wallofthe dome |32 also prevents Vdeposits of solid substances against the wall of the dome in such manner as might result in` an accumulation :of suicient thickness to reach across the Vgap and contact the rapidly rotating milling head.

Thus the dangers of frictional-burningof the mill feed materiah and development of undesirablemill temperatures and. cloggingof the machine are obviated. 1 v l The portion of the `mill feed `material passing through the by-pass ports |30 in the dome is returned -by way of .the conduit I4! .to theoriginal mill'f'eedsupply tanl;` |135. 4The remainder of the incoming mill feed material travels downwardly into.. the milling yzone between'..the surfacesy 50 and `|22 of the head 50 and stator .|20 respectively. The .stator |20 .isf adjustable vertically in the -saddle 90 to provide .the :desired width of m'illing'gap between lthe milling surfaces, and the angular relation between the ksaddle and the iframe I as well asA the lateral and longitudinal relativepositions of the stator in the saddle, are adjustable' to obtain perfect conformity between -therotor and stator surfaces. Thus a gap width of the minutest degree may be established uniformly throughout theextent of the milling zone without frictional contacts between portions of .the .relatively moving members. Hence, prohibitive .frictiongenerated heating of the mill is `avoided,.'andza .moreuniformly fine product is obtained.

In the lower end portion of the saddle 90 an annular .collecting trough |50 is provided to conduct the discharge from the milling Zone toout- `let ports |52 at opposite sides of the machine, from whence the mill product may be conveniently collected. A covering for the bearings 32 and :33 is provided by afflange |60 formed on the saddle S0 and adapted to encircle. the shaft 30. 'Ihe flange |60 is provided with-asealing ring |62 of conventional design, for preventing the passage of foreign material downwardly and Apast the flange into the bearings. A downwardly extending apron |64is attached to the lower end ofthe milling head 50 by means of studs |65 yand extends below the upper margin of the flange |60, thus preventing the return of material discharged from vthe milling` zone upwardly and in towardthe shaft 30 above the flange |50. A retaining plate |66 maintains the sealing ring .|02 inoperable position within the flange |60.

l Means for lubricating the Vbearings 32 and 33 yare provided by av bell-shaped slinger ring fixedly mounteduponthe shaft 30 below the bearing 33 by means of a sleeve |12 between the ring- 16 and the bearing race 35.v The lower laterally extending ange portion of the ring |10 is adapted to revolve in a well provided in .the frame I0 by an upturned flange |10. An 11p-take tube |18 is in open communication at its lower end with the well |16 and at its upper end with the annular chamber` |80 formed between .the .flange |02` of the frame and the shaft 30 above the bearing 32. A supply of lubricating oil of sufficient quantity to fill the well |16 lis introduced through an inlet connection |32 on the upftake tube. Rotation of the-shaft 30 and the slingervring |10causes a constantly moving supply of oil to be forced upwardly through the uptake tube to its point of discharge above the bearing 32 in accordance with the principles of centrifugal action. v`The forcesl of gravity then lcause the oil t work its way downwardly through the members of the bearing 32 and thence downwardly along shaft 30 to the bearing 33 and thence to'return again to the sump |16.v y

Hand-,hole plates I5 are providedV in the sides of the lframe member |0 to provide convenient means of access to the top of the motor l2A and the coupling 42. Air vents |1 are provided in the hand-hole covers I5 to assist in connection with the ventilationr of the motor |2.

As illustrated in Fig. 1, means are provided to regulate the temperature of the stator and the dome |32 as comprising a fluid conducting chamber |2| interiorly ofthe stator |20 and a similar fluid conducting chamber |35 formed interiorly of the dome |320 A fluid inlet conduit |90 is provided for introducing a constantly running supplylof `iiuid'into the lower section of the chamber` |2|1of the stator. An outlet port I9! formed inl-the upper end of the stator |20 com-v municates. with an inlet port |92 through the wall of the dome |32, and an outlet port |93 is provided through an opposite wall portion of the dome |32 for connection with a discharge conduit means of any conventional type. Thus a temperature-regulating fluid may be circulated through the stationary working members of the mill. In some cases this will be a cooling fluid to prevent the building up of excessive temperatures in the mill; and in some cases the uid will be a heating medium to maintain the mill at a temperature prerequisite to the proper handling of certain materials.

Fig. 4 illustrates a form of milling head construction identical wth that shown in Fig. 1 except that in addition, means for regulating the temperature of the milling head are provided. A duplex packing gland 200 embraces the lower end of the shaft 30 in liquid tight relation by means of packing rings 202. An inlet port 204 is in open communication with an annular liquid chamber 206 which is formed jointly by a wall of the gland and the adjacent portion of the shaft 30. The shaft 30 is provided with a central longitudinal bore in which is fitted a section of double compartment tubing 208, thus defining a pair of separate longitudinal openings 2|0 and 2|| through the shaft. The opening 2|0 is in open communication with the iiuid inlet chamber 206 by means of a port 2|2. The milling head 50 is provided with an interior chamber 2|4 for fiuid containing purposes. A port 2|6 in open communication with the opening 2|0 and the chamber 2|4 is provided in the lower section of the head, and a port 2| 8 in the upper end of the head provides -communication means between the chamber 2|4 and the upper end of the shaft opening 2| At its lower end, the longitudinal opening 2|| is in open communication by means of a port 2|9 with an outlet chamber 220 and an outlet connection 22|. Thus a cooling or heating iiuid medium may be forced through the inlet 204 and upwardly through opening 2|0, and thence circulated throughout the interior of the milling head 50 and returned through the longitudinal opening 2|| and discharged through the outlet connection 220 while the mill is operating, to assist the fluid circulating through the stator in controlling the temperature of the mill.

Although only one form of the invention has been shown and described in detail it will thus be apparent to those skilled in the art that the invention is not so limited but that various changes can be made therein without departing from thespirit of the invention or from the scope of the appended claims.

I claim:

1. A mill for disintegrating substances comprising a fixed member having a truncated coneshaped working surface, a rotatable member having a truncated cone-shaped working surface adjacent the first mentioned surface and defining a milling path for the mill feed material therebetween, the apex portions of said fixed and rotatable members providing a pre-milling chamber adjacent the inlet ends of said working surfaces for distributing mill feed material evenly into said `milling path, a mill feed material' inlet at the apex of said fixed member for discharging mill feed material into said pre-milling chamber axially of said mill, by-pass conduits formed in the apex portion of said rotatable member for receiving a portion of the mill feed passing through said inlet and diverting it transversely of said mill axis and impelling it across said pre-milling chamber as a result of centrifugal action set up by rapid rotation of said rotatable member, and radially disposed outlet ports through the walls of said fixed member in the region of the pre-milling chamber for receiving a portion of the mill feed material passing through said inlet and conducting said portion of said mill feed material to the original mill feed supply.

2. A mill for fluid materials comprising inner and outer cone-shaped members in telescopic relation and relatively movable about a coincident longitudinal axis and defining a millingl path therebetween, a mill feed material inlet adjacent the apexes of said members for discharging mill feed material axially of said milland into said milling path, a by-passing conduit through the inner of said members having an inlet port in line with said mill feed material inlet and adapted to receive a portion thereof and to divert it from said milling path, said by-passing conduit having another portion adapted to redirect said by-passed portionof said mill feed material and to discharge it into said milling path in a direction transversely thereof, and a radially disposed outlet port through the wall of the outer of said members adapted to receive ai fraction of the mill feed material discharged by, said by-pass conduit and conducting said fraction of said mill feed material to the original feed supply.

3. A mill for fluid substances comprising a fixed member having a truncated cone-shaped working surface, a rotatable member having a truncated cone-shaped working surface closely adjacent the first mentioned surface and defining a milling path for the mill feed material therebetween, an inlet for said mill feed material at the apex of said fixed memberr working surface in the form of a conduit of circular section having a discharge opening so arranged as to introduce the mill feed material into the mill in a direction axially of said mill, and a conduit in said rotatable member having a mill feed receiving opening of circular section at the apex thereof `and lin line with said discharge opening, the diameter of said receiving opening being substantially less than the diameter of said discharge opening, said rotatable member conduit being adapted to receive a portion of said mill feed material under dynamic pressure forces and to divert it away from thev milling path between said working surfaces and to subsequently redirect and impel said diverted portion of said mill feed material transversely across said milling path and against the walls of said fixed member.

4. A mill for fluid substances comprising a fixed member having a cone-shaped working surface, a rotatable member having a cone-shaped working surface closely adjacent the first mentioned surface and defining a milling path for the mill feed substances therebetween, means for introducing mill feed substance between said working surfaces including an inlet conduit at the apex of said fixed member working surface having a discharge opening directed axially of said mill, and conduit means in said rotatable member having an inlet opening in line with said fixed member inlet conduit opening of substantially lesser sectional area than the latter for receiving a portion of the mill feed material under dynamic pressure forces and diverting it away from the milling path and subsequently directing said diverted portion of said mill feed material transverselv nf said milling path.

EDWARD A. BUTLER. 

